Factor IX chromogenic assay
AssigneeDade International Inc.
InventorH. C. Hemker
Life of this patent
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Abstract
A chromogenic assay for determination of blood coagulation Factor IX (christmas factor) utilizes Factor Xa formed by the conversion of Factor X by activated Factor IX and Factor VIII to cleave a chromogenic substrate. The sample is combined into a mixture with Factor XIa in the presence of Factor IIa (thrombin), incubated, combined with Factor X and Factor VIII, and incubated. A thrombin inhibitor, and an indicator agent which reacts with Factor Xa, are added and the resulting signal measured and correlated to the level of Factor IX in the sample.
Claims16
A method for determining coagulation Factor IX in a blood, serum, plasma or other fluid sample suspected of containing Factor IX comprising:
- a) combining into a mixture said fluid sample with blood coagulation Factor XIa in the presence of calcium ions and Factor IIa;
- b) incubating the mixture for a time sufficient to convert substantially all of the Factor IX to Factor IXa;
- c) further combining the mixture with Factor X in the presence of phospholipids, Factor VIII and calcium ions;
- d) incubating the mixture for a time sufficient to convert all or a portion of the Factor X to Factor Xa;
- e) adding to the mixture a Factor IIa inhibitor and an indicator agent capable of reacting chemically with the Factor Xa to generate a measurable signal;
- f) measuring the signal;
- and
- g) correlating the measured signal molecule to the level of blood coagulation Factor IX in the fluid sample.
A kit for performing a Factor IX assay in a blood, serum, plasma or other fluid sample suspected of containing said Factor IX comprising:
- a) a vial containing Factor XIa and Factor IIa;
- b) a second vial containing Factors VIII and X;
- and
- c) a third vial containing a Factor IIa inhibitor and an indicator agent capable of reacting chemically with Factor Xa to produce a measurable signal.
A kit for performing a Factor IX assay in a blood, serum, plasma or other fluid sample suspected of containing Factor IX comprising:
- a) a vial containing Factor XIa and Factor IIa;
- b) a second vial containing Factors VIII and X;
- c) a third vial containing a Factor IIa inhibitor and an indicator agent capable of reacting chemically with Factor Xa to produce a signal molecule;
- and
- d) a fourth vial containing a quenching composition to stop conversion of said Factor X to Factor Xa.
Dependencies are inferred from the claim text.